Many methods of coding voice signals are known which allow the number of bits required for coding said signals to be minimized while still affording sufficient precision to enable the decoded signal to faithfully reproduce the input signal. One such method is the subband coding scheme described in an article by D. Esteban and C. Galand entitled "32 kbps CCITT Compatible Split Band Coding" in Proceedings of the 1978 IEEE International Conference on Acoustics, Speech and Signal Processing, Tulsa, Okla., Apr. 10-12, 1978. Basically, this scheme consists in splitting the low-frequency band (telephone channel bandwidth) of the signal to be processed into several subbands and in optimally quantifying the information contained in each subband. Also, the output signal from each subband is re-sampled (by means of a so-called decimation operation) so as to cause the information rate to remain constant. Although this subband coding scheme yields very good results, still better results can be obtained by making use of the basic properties of voice signals and, in particular, of the characteristics of the so-called baseband.